1. Field of the Invention
The present invention relates to a printing apparatus capable of processing document image data received from the outside and stored, a data processing method for the printing apparatus and a storage medium.
2. Description of the Related Art
A printing apparatus temporarily stores data before printed in a memory as document image data. While in this state, the document image data is generated from information of a print job. The format of the document image data is the one internationally standardized based on specifications of portable document format (PDF) data. The printing apparatus generates intermediate data from the document image data, performs rendering processing on the intermediate data, and outputs an image. An intermediate data generation time and a rendering time can be estimated from the details, a number of pages, and the like of the document image data stored in the memory.
There is an issue that when intermediate data for printing is generated from the document image data stored in advance in the memory, a printing time does not keep up with an engine speed depending on a job. The printing time is a value obtained by adding the intermediate data generation time and the rendering time. As a solution, there is such a method for changing the intermediate data to adjust the rendering time, when the printing time cannot keep up with the engine speed at respective pages.
Japanese Patent Application Laid-Open No. 09-218861 discusses a method for measuring an intermediate data generation time and a rendering time of print data and improving the rendering time by changing the intermediate data, when the measured data has similar tendency to the past data which took long printing time. In this method, since the printing method is changed based on the past data, the tendency for the data which has never been handled is not understood, and accordingly countermeasures cannot be taken.
When the above-described document image data is used in the printing apparatus, the data can be managed for each item of objects. In other words, the document image data can be used as higher level data of conventional intermediate data. By using the document image data in this manner, even data which conventionally takes long processing time for printing can be changed.
There are several methods for optimizing the document image data. The optimization method can change the rendering time by changing contents of the intermediate data for each level. The rendering time of a job including a plurality of pages which has never been processed in the past can be improved with use of the optimization level.
However, if the rendering time becomes fast by processing the document image data as described above, an idle time is generated from a difference between the intermediate data generation time and the rendering time. There is an issue that in a case where such an idle time is generated and if the rendering time is not adjusted to keep up with a timing at which image formation is performed on a conveyed sheet by the printing apparatus, processing waiting for being performed occurs during the intermediate data generation or during the rendering and printing time is delayed.